Aqueous emulsions

ABSTRACT

AQUEOUS EMULSIONS ARE PROVIDED WHICH CONTAIN   (A) A METHYLOLAMINOTRIAZINE (B) A WAXY SUBSTANCE (C) A WATER-SOLUBLE NON-IONIC POLYETHYLENE GLYCOL COMPOUND AND (D) AN ALKYLBENZENESULFONIC ACID SALT.   IN A DILUTE FORM, AND ADDITIONALLY CONTAINING A CURING CATALYST, THESE EMULSIONS SERVE FOR THE PRODUCTION OF WASH-FAST, WATER-REPELLENT FINISHES ON FIBER MATERIALS.

Patented May 2, 1972 US. Cl. 252-3115 13 Claims ABSTRACT OF THE DISCLOSURE Aqueous emulsions are provided which contain (a) a methylolaminotriazine (b) a waxy substance a water-soluble non-ionic polyethylene glycol compound and (d) an alkylbenzenesulfonic acid salt.

In a dilute form, and additionally containing a curing catalyst, these emulsions serve for the production of wash-fast, water-repellent finishes on fiber materials.

The subject of the invention is aqueous emulsions with a total solids content of to 40 percent by weight, characterised in that they contain the following in relation to the dry weight of the components (a) to (d):

(a) 17 to 86% of at least one reaction product of a methylolaminotriazine with higher fatty acids, higher fatty acid amides and/or higher alcohols,

(b) 8 to 77% of at least one hydrophobic waxy substance which is soluble in component (a),

(c) 0.7 to 14% of at least one water-soluble non-ionic polyethylene glycol compound, which per molecule contains 6 to 200 CH CH -O groups and at least one hydrophobic residue of an organic compound which has been produced by splitting off a reactive hydrogen atom, and

(d) 0.4 to 13% of at least one alkylbenzenesulphonic acid salt of a colourless metal cation, wherein the alkyl residue or residues in total contain at least 8 carbon atoms,

with the content of components (a) and (b) together amounting to 85 to 96% and of components (c) and (d) together amounting to 4.5 to relative to the dry weight.

Possible components (a) are especially methylolaminotriazines esterified with higher fatty acids and/ or etherified with higher alcohols. Herein, derivatives of formoguanamine, acetoguanamine or benzoguanamine, but preferably of melamine, are for example used. Methylol groups of these compounds are esterified with higher fatty acids which contain at least 12 carbon atoms or are etherified with higher alcohols, that is to say alkanols containing at least 12 carbon atoms. In addition to the methylol groups modified in this way, the triazine compounds advantageously further contain methylol groups etherified with alkanols containing at most 4 carbon atoms, such as butanol, isopropanol or especially methanol. As a rule it is advisable for the methylol groups present to be further substituted in the indicated manner to the extent of at least 75%, in particular to be esterified with higher fatty acids or etherified with higher alcohols to the extent of 15 to 50%. As examples of higher acyl residues, those of fatty acids with 12 to 24 carbon atoms should above all be mentioned, for example lauric, myristic, palmitic or stearic acid, and the residues do not have to be all the same. The esters obtainable from methylolmelamineethers and stearic acid are particularly suitable, especially those which are obtained by reaction of highly methylated methylolmelamines with stearic acid, and so-called technical stearic acid of commercially available quality can also be used with practically the same result as pure stearic acid. As examples of a higher alcohol with 12 to 24 carbon atoms, lauryl, myristyl, palmityl, stearyl or arachyl alcohol may be mentioned, and here again the residues do not all have to be the same, and technical fatty alcohols can again be used. The molecular chain of the higher alcohol can optionally also be interrupted by nitrogen atoms, that is to say instead of the actual alcohols it is for example also possible to use fatty acid methylolamides as etherifying agents for the manufacture of the component (a). Possible fatty acids are here the same as those mentioned for the acylation. Stearic acid methylolamide for example represents such a use. The fatty acid amides which are also suitable for the reaction with a methylolaminotriazine are derived from the same fatty acids as those used for the etherification.

As substance(b), it is possible to use the known waxy agents for conferring hydrophobic properties, such as for example beeswax and especially parafiins of melting point advantageously between about 45 and C. By a waxy substance there is as a rule understood a hydrophobic fusible substance which can be plastically deformed and possesses a smooth surface which can be scratched.

Component (c) as a rule consists of reaction products of ethylene oxide with organic compounds which possess at least one reactive hydrogen atom and a hydrophobic residue. However, appropriate reaction products of polyethylene glycol compounds of the indicated nature can also be used.

Particular interest attaches to water-soluble polyethylene glycol compounds which per molecule contain 8 to 100, preferably 9 to 80, but especially 12 to 60 and even only 20 to 50 CH -CH O-- groups.

Advantageously, component (0) contains, as the hydrophobic residue, at least one residue which has been produced by splitting off a hydrogen atom from a hydroxyl, mercapto, carboxyl, carboxyamido or amino group of an organic compound. The organic compound with the reactive hydrogen atom and the hydrophobic residue thus for example is an alcohol, a thioalcohol, a carboxylic acid, a carboxylic acid amide or an amine. Alkylphenols, especially a tributylphenol, are particularly suitable. However, other organic compounds of the indicated nature can also be employed, for example nonylphenol, di-tert,-butyl-pcresol, alkylthiophenols, stearyl alcohol, oleyl alcohol, stearic acid, stearic acid hydroxyethylamide, stearylamine or oleylamine, hydroabietylamine or hydroabietyl alcohol.

Particularly valuable components (c) are the watersoluble polyethylene glycol compounds which per molecule contain 20 to 50 CH CH O- groups and at least one phenoxy residue which is optionally substituted by alkyl groups. Amongst these compounds, a Water-soluble polyethylene glycol compound which per molecule contains 30 CH CH -O- groups and a tributylphenoxy residue has proved particularly advantageous.

As component (d), an alkylbenzenesulphonic acid salt of a colourless metal cation of a metal of Groups Ia, Ha, IIb, IIIa, IVa or IV!) of the periodic system is preferably used. The alkylbenzenesulphonic acid salts of lithium, potassium, sodium, caesium, magnesium, calcium, barium, zinc, cadmium, aluminium, tin, lead, zirconium or titanium have here proved particularly suitable. The component (d) advantageously contains a single alkyl residue with 8 to 18, preferably 12, carbon atoms.

The sodium, potassium or especially calcium salts of a dodecylbenzenesulphonic acid have here proved to be of particular interest. The alkyl residue, or the dodecyl residue, can be branched or unbranched. As a rule, the residues in the case of dodecylbenzenesulphonic acid are either n-dodecyl residues or branched residues which are obtained by reaction of tetrapropylene with benzene and subsequent sulphonation and neutralisation.

Preferably, the components (a) to (d) are used in such a way that the aqueous emulsions contain, relative to the dry Weight of components (a) to (d), 34 to 48% of component (a), 48 to 58% of component (b), 1.8 to 11% of component (c) and 1.3 to 9% component (d), with the content of components (a) and (b) together amounting to 85 to 96% and of components (c) and (d) together amounting to 4.5 to 15%, relative to the dry weight. Depending on the content, the aqueous emulsions are mobile to 35% strength) or viscous (35 to 40% strength).

In manufacturing the emulsions, the preferred procedure is that firstly the substances (c) and (d) which are genuinely or colloidally soluble in water, and also, where appropriate, a small amount of a base, for example an alkali hydroxide such as sodium or potassium hydroxide, in order to avoid too low a pH value and hence premature curing, are added to the requisite amount of water and that then components (a) and (b) are added at elevated temperature, successively or preferably conjointly (in the form of a warmed melt). Immediate homogenisation of the corresponding two-phase system should be ensured with the aid of a high-efficiency stirrer or some other suitable device. Heat is appropriately supplied in such a way that the emulsion temperature is close to the boiling point but does not reach the latter. During the emulsification process or especially thereafter, yet further substances, for example anti-foaming agents, can be added.

For use, the emulsion is diluted with cold or warm water and a curing catalyst is added so that the resulting bath shows a solids content of 1 to 18 percent by weight.

As curing catalyst for the methylol compound (a), it is possible to use the known acid or potentially acid aminoplastic curing agents, for example ammonium salts of strong acids such as ammonium thiocyanate or ammonium chloride, zinc nitrate, zinc chloride, zinc fluoborate, magnesium chloride, hydrochloric acid, phosphoric acid or formic acid. Aluminium salts, for example aluminium chloride or especially aluminium sulfate, prove particularly advantageous. The curing catalyst is appropriately used in amounts of l to 5% relative to the dry weight of the treatment bath.

The baths manufactured in this way by dilution of the aqueous emulsions and by addition of a curing catalyst serve for the production of a wash-fast, water-repellent finish on fibre materials, the fibre material being treated with these aqueous baths, which now show a solids content of 1 to 18 percent by weight.

The treatment of the fibre material, for example cotton of fibres of regenerated cellulose, with the baths of the indicated composition can take place at room temperature or slightly elevated temperature, for example to C., using the customary known devices, appropriately by impregnation on a padder. The weight increase is advantageously 60 to 100%.

The fibre material impregnated in this way can now first be dried, for example at room temperature or at 4 60 to C., before it is subjected to a heat treatment, for example at to 180 C. for 20 to 1 minutes.

The finishes obtainable according to the present process impart good water repellency to the fibre materials and are wash-fast.

EXAMPLE 1 Manufacturing instruction for an emulsion The manufacture of 100 g. of an emulsion is described, for which the data from the subsequent compilations and Tables I to IV must be employed. .5 g. of alkylbenzenesulphonate (=component (d)) and e g. of the component (c) which acts as emulsifier are initially introduced into a vessel which can be heated and possesses a propeller stirrer, the speed of rotation of which is infinitely variable, and are diluted with 32 g. of water and warmed to 95 C.

A homogeneous melt of m g. of a condensation product M (:component (a)), the manufacture of which is described below, and of p g. of parafiin (=component (b)), warmed to about 105 C., is now poured into this aqueous emulsifier-sulphonate solution, and stirred at increasing speed of rotation until an emulsion is formed, care being taken, through regulating the external heating, that the emulsion does not start to boil. An emulsion is produced, which is thereafter diluted with 10 g. of water at above 80 C., at a low speed of stirring. This somewhat more dilute solution is new again stirred at high speed of rotation and then again stirred at low speed of rotation with 11 to 25 g. of water at above 80 C., so that 100 g. of emulsion are produced. This emulsion is allowed to cooled by leaving it to stand. The emulsion manufactured according to this process can be diluted with cold or warm water and shows the properties listed in the examples which follow.

The condensation products M (esterified melamine resins M I to M V, etherified melamine resins M VI to M X, and esterified and etherified melamine resins M XI to M XII) are manufactured as follows:

M I: 324 parts (1 mol) of finely powdered hexamethylolmelamine are introduced with stirring into 2000 parts by volume of methanol containing 100 parts by volume of 30% strength hydrochloric acid. After 10 minutes the methylol compound has dissolved. The solution is immediately stirred with about 160 parts of anhydrous sodium carbonate until it reacts neutral to litmus. The salt which has separted out is filtered oif and the solution is evaporated in vacuo to a syrup of at least 98% strength. The salt which has now additionally separated out is removed by filtering whilst warm. 100 parts of this methylolmelamine-methyl-ether are heated with parts of stearic acid in a vacuum of 10 to 20 mm. Hg to 190 to 200 C. until the residual acid number is 5 to 8.

M II: 390 g. (1 mol) of the methylolmelamine-methylether described under M I are warmed with 270 g. (1 mol) of technical stearic acid in a vacuum of 25 to 30 mm. Hg pressure to l95200 C. until the residual acid number is 2 to 3, which is the case after 3 hours warming.

M III: 390 g. (1 mol) of the methylolmelamine-meth yl-ether described under M I are warmed with 242 g. (1 mol) of myristic acid to 195-200 C. in a vacuum of 25 to 30 mm. Hg pressure until the residual acid number is 2 to 3.

M IV: 350 g. of stearic acid ester according to M I (containing about 0.0475 mol of melamine and 67.5 g. (0.25 mol) of stearic acid are warmed to -l65 C. in a vacuum of 25 to 30 mm. Hg pressure until the residual acid number is 3 to 4, which is the case after warming for 3 hours.

M V: 25 g. (0.2 mol) of melamine and 46.2 g. (1.5 mols) of paraformaldehydc of 97.5% strength are suspended in g. (2.36 mols) of isobutanol and together with 134 g. (0.5 mol) of a 1:1 mixture of palmitic acid and stearic acid are warmed to 100 C. over the course of minutes whilst stirring. The mixture is warmed from 100 C. to 160 C. over the course of a further 100 minutes, in the course of which 151 g. of distillate are already obtained. Thereafter the contents of the flask are warmed to 160-163 C. over the course of a further 5 hours in a vacuum of 30 to 50 mm. Hg pressure, during which a further 63 g. of distillate are obtained. During this time the reaction material becomes more viscous without however gelling. A sample of the mixture shows an acid number of 14.2. The condensation is ended by cooling the reaction vessel. A waxy mass which gives a clear solution in benzene is obtained.

M VI: 195 g. (V2 mol) of the methylolmelamine-methyl-ether described under M I are warmed with 155 g. of a synthetic arachyl alcohol to 195-200 C. over the course of 4 hours in a vacuum of 30 to 35 mm. Hg presure, whilst stirring. After cooling, a viscous mass is obtained which gives a clear solution in benzene.

M VII: 250 g. (/2 mol) of a 75% strength solution in butanol of a hexamethylolmelamine-butyl-ether with about 2 to 3 butyl groups are warmed to 120 C. with 155 g. of a synthetic arachyl alcohol over the course of 1 hour in a vacuum of 30 mm. Hg pressure, during which butanol distils off. Thereafter the mixture is further warmed for 8 hours, whereupon, after cooling, a pale yellow viscous mass is obtained which gives a clear solution in benzene.

M VIH: 195 g. (V: mol) of the methylolmelaminemethyl-ether described under M I are warmed to 195- 200 C. with 105 g. /2 mol) of myristyl alcohol over the course of 6 hours in a vacuum of 30 to 35 mm. Hg pressure, whilst stirring. An almost colourless highly viscous mass is obtained, which gives a clear solution in benzene and in paraffin.

M IX: 252 g. (0.5 mol) of an 80% strength solution (viscosity index at 25 C.: 35 cp.) in butanol of a low viscosity hexamethylolmelamine-butyl-ether with about 2 butyl groups are condensed with 186 .g. of a synthetic arachyl alcohol over the course of 90 minutes at 120 to 125 C. in a vacuum of 30 mm. Hg pressure. 368 g. of a pale yellow mass which (at C.) resemblespetroleum jelly and which gives a clear solution in warm paraffin and is insoluble in acetone are obtained. The original uncondensed reaction mixture is insoluble in paraflin but gives a clear solution in acetone. The reaction material shows a viscosity index of 890 cp. at 60 C.

M X: An analogous condensation product was 134 g. (0.5 mol) of technical fatty alcohol, containing 63% of palmityl alcohol, 30 to 35% of stearyl alcohol and small amounts of lauryl alcohol and myristyl alcohol can be manufactured in the same manner as described under M IX. 294 g. of a colourless waxy mass which gives a clear solution in Warm benzene and in warm parafiin are obtained.

M XI: 350 g. of stearic acid ester according to M I (containing about 0.475 mol of melamine) and 92.5 g. (0.25 mol) of a synthetic arachyl alcohol are warmed for 3 hours to 160-165 C. in a vacuum of to mm. Hg pressure. 432 g. of a pale yellow waxy mass which gives a clear solution in warm paraflin and in warm benzene are obtained. Acid number of a sample: 3.2.

M XII: An analogous condensation product can be manufactured in the same manner as described under M XI with 67.5 g. (0.25 mol) of technical fatty alcohol containing 63% of palmityl alcohol, 30 to of stearyl alcohol and small amounts of lauryl alcohol and myristyl alcohol. 404 g. of an almost colourless waxy mass which gives a clear solution in warm parafiin and shows an acid number of 1.6 are obtained.

The aqueous emulsions 1.1 to 1.13 have the following compositions:

Component ((1): s=1.5 g. of calcium dodecylbenzenesulphonate.

EEEEEZEEZEEEE gn aggfiaa w The aqueous emulsions 1.14 to 1.27 have the following compositions:

TABLE II Components, in g.

Ca dodeeyl- Emulsion benzene- E I- Paraffin, number sulphonate E XIII 6062 C. M I M IX The components (c) (E I-E XIII) have the following compositions:

TABLE III Component (0) Addition products of z mols of Emulsion ethylene number E oxide to I mol 0i- 1.14... I 30 Tributylphcnol. 1.15. I 30 D0. 1.16. II 50 Do. 1.17. III 18 Do. 1.18... IV 15 Hydroabietyl alcohol. 1.19. V 30 Nonylphenol. 1.20. VI Do. 1.21. VII 15 Di-tert.-buty l-p-cresol. 1.22. VIII 35 Stearyl alcohol. 1.23. IX 80 Oleyl alcohol. 1.24. X 40 Stearylaminc. 1.25. XI 80 Hydroabietylamme. 1.26. XII 80 Oleylamine. 1.27 XIII 30 Mixture of 10% stearylamme, 56%

arachylamine, 35% behenylamine.

The aqueous emulsions 1.28 to 1.46 have the following compositions:

Component (d) Amount,

Composition B a dodecylbenzene sulphonate. Zn dodecylbenzene sulphonate.

C d dodeeylbenzenesulphonate. Pb dotiecylbenzenesulphonate. Mg dodeeylbenzenesulphonate. Zr dodecylbenzenesulphouate.

Al dodccylbenzenesulphonate. Sn dodecylhenzenesulphonate. Ti dodecylbenzencsulphonate. Na dodecylbenzenesulphonate. K dodecylbenzenesulphonate.

Li dodecylbenzenesulphonate. Cs dodecylbenzenesulphonate. Ca n-undecylbenzenesulphonate. Na n-undecylbcnzenesulphonate. Ca n-dodecylbenzenesulphonate. Na n-dodecylbenzenesulphonate. Na tliaodecylbenzenesulphonate.

Component (c): in each case 1.13 g. of E I.

Component (b): in each case 20 g. of a parafiin of melting point 60 to 62 C.

Component (a): in each case 10 g. of M I.

EXAMPLE 2 Emulsions 2.1 to 2.11 are manufactured in the same way as in Example 1 from 10 g. of component (a), 20 g.

The condensation product M XIII is manufactured as follows:

250 g. (0.15 mol) of a 75% strength solution in nbutanol of a hexamethylolmelamine-n-butyl-ether with about 2 to 3 n-butyl groups are warmed for one hour to 120 C. with 162 g. of behenyl alcohol in a vacuum of 30 mm. Hg pressure, in the course of which n-butanol distils off. Thereafter the mixture is further warmed for 8 hours, whereupon, after cooling, a yellowish viscous mass is obtained which gives a clear solution in benzene.

The condensation product M XIV is manufactured like the condensation product M VIII, except that in place of myristyl alcohol stearic acid amide is employed.

The components E XIV to XVIII have the following composition:

TABLE VI Component faddition product X mols of To 1 mol of- Dodecylmercaptan. Nonylphenol.

O leic acid.

Oleic acid amide. Stearic acid amide.

EXAMPLE 3 90 g. of an emulsion manufactured according to Example 1 are diluted with water at room temperature, with the addition of 40% strength acetic acid until a pH value of is reached, in such a way that after addition of g. of a 20% strength aluminium sulphate solution an impregnating bath of 1 litre is obtained. This is introduced into the trough of a three-roll padder. A cotton gabardine strip passes through the padder, with the uptake of impregnating liquid being 70%. After drying at 80 C., curing is carried out for 5 minutes at 150 C. A material with a water-repellent finish is obtained.

The water-repellent properties of the fabrics are determined using the spray test, on the basis of the water absorbency after brief sprinkling:

cm. long, weighed samples of fabric are held at both ends with 2 clamps weighing 95 g. and laid over two rods. Thereafter the fabric samples are sprinkled with 500 ml. of water and freed of adhering drops, and the moist sample is weighed. The weight increase, taken as a measure of the hydrophobic effect, is specified in percent of the dry fabric.

TABLE VII Percent water absorption Fabric r Emulsion washed 0 at the boil G./l. Unwashed in washing in bath fabric machine Nmiallaer 1.8. 90 2 8 1.9- 90 7 9 1.1 90 3 2 1 0 1.11 so 4. 4 1.1 90 3 2 1.1 90 4 4 1.1 90 2 2 1.15 90 2 2 1.1 90 3 4 1.2 90 3 3 20 1.2 120 2 8 1.2 120 1 8 1.3 120 2 8 1.3 20 2 12 1.3 120 2 6 1.33. 120 2 8 }20 2 8 20 2 8 2a 1.36 120 2 5 1.3 120 2 10 1.3 120 2 9 1.3 120 3 9 1.4 120 2 9 1.4 120 2 10 1.42 120 2 8 1.43 120 2 9 1.44.-.. 120 2 4 1.45.. 120 2 6 1.46 120 2 5 Untreated fabric 120 120 EXAMPLE 4 Cotton fabrics are finished with the emulsions according to Example 2 in the same way as described in Example 3, and the following results are thereby obtained:

TABLE VIII Percent water absorption Fabric Emulsion washed at C. in G./l. in Unwashed washing bat abric machine finished analogously and the A viscous fabric is also following result is obtained:

Percent Water absorption Cotton fabrics are finished in the same way as described in Example 3, but instead of using the 20 g. of a 20% strength aluminium sulphate solution mentioned in Example 3, the catalysts listed below in the table which follows are used:

6. An aqueous emulsion according to claim 1, characterized in that it contains parafiin as component (b).

I claim:

1. An aqueous emulsion, with a total solids content of 10 to 40% by weight, characterized in that it contains the following relative to the dry weight of components (a) to (d):

(a) 17 to 86% of a reaction product of a methylolaminotriazine with at least one member selected from the group consisting of a higher fatty acid, a higher fatty acid amide and a higher alcohol,

(b) 8 to 77% by weight of a hydrophobic waxy substance which is soluble in component (a),

(c) 0.7 to 14% by Weight of a water-soluble non-ionic polyethylene glycol compound, which per molecule contains -6 to 200 -CH CH O- groups and at least one hydrophobic radical which has been produced by splitting oil a hydrogen atom from a hydroxyl, mercapto, carboxyl, carboxyamido or amino group of an organic compound, and

(d) 0.4 to 13% of an alkylbenzenesulfonic acid salt of a colorless metal cation, in which the alkyl radical or radicals in total contain at least 8 carbon atoms,

with the content of components (a) and (b) together amounting to '85 to 96% and of components (c) and (d) together amounting to 4.5 to 15%, relative to the dry weight.

2. An aqueous emulsion according to claim 1, characterized in that it contains a methylolmelamine as component (a) which is reacted with fatty acids, fatty acid amides and/or alcohols which contain at least 12 carbon atoms each.

3. An aqueous emulsion according to claim 1, characterized in that it contains a methylolmelamine as component (a) which is esterified with fatty acids and/ or etherified with alkanols, which each contain 12 to 24 carbon atoms.

4. An aqueous emulsion according to claim 3, characterized in that it contains a methylolmelamine as component (a) which is further etherified with an alkanol which contains at most 4 carbon atoms.

5. An aqueous emulsion according to claim 1, characterized in that it contains a methylolmelamine as component (a) which is an ester obtainable from methylolmelamine-methylether and stearic acid.

7. An aqueous emulsion according to claim 1, characterized in that component (c) contains 12 to groups per molecule.

8. An aqueous emulsion according to claim 1, characterized in that component (c) contains at least one hydrophobic radical which has been produced by splitting off a hydrogen atom from a hydroxyl or amino group of a phenol, alkanol or alkylamine.

9. An aqueous emulsion according to claim 1, characterized in that component (e) is a water-soluble polyethylene glycol compound which contains 30 groups and one tributylphenoxy radical per molecule.

10. An aqueous emulsion according to claim 1, characterized in that component (d) is an alkylbenzenesulfonic acid salt of a colorless metal cation of a metal of Groups Ia, Ila, IIb, IIIa, IVa or Nb of the Periodic Table having 8 to 18 carbon atoms in the alkyl radical.

11. An aqueous emulsion according to claim 1, characterized in that component (d) is an alkylbenzenesulfonic acid salt of lithium, sodium, potassium, caesium, magnesium, calcium, barium, zinc, cadmium, aluminum, tin, lead, zirconium or titanium, having 8 to 1-8 carbon atoms in the alkyl radical.

12. An aqueous emulsion according to claim 1, characterized in that component (d) contains a single alkyl radi-j cal containing 12 carbon atoms.

13. An aqueous emulsion according to claim 1, characterized in that component (d) is the calcium, sodium or potassium salt of a dodecylbenzenesulfonic acid.

References Cited UNITED STATES PATENTS 1,970,578 8/1934 Schoeller et a1. 260-98 2,503,246 4/ 1950 Craig 25 23 1 1 .5 2,861,054 11/1958 Rust et al. 260249.6

JOHN D. WELSH, Primary Examiner US. Cl. X.R.

UNITED STATES PATENT OFFICE CERTIFTQATE or CORRECTION Patent No. 0; Dated. May 2, 1972 Inve t f( ARMIN HIESTAND,

It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 1, in the heading, lines 4 end 5, "assignor to Ciba Limited, Basel, Switzerland". should read assignor to Ciba-Geig-y AG, Basie, Switzerland 3 Signed and sealed thisisth da of b einbeg 1973. I

(SEAL) Attest: I

EDWARD M. FLETCHERJR RENE 13-. TEGTMEYER Attesting Officer I Acting Commissioner of Patent FORM Po-105o (10-69) uscoMM-Dc 60B76-P69 u.s. sovnn nzu-r rnmnu a oFric: ma osu-su. 

